We intend to utilize extremely sensitive fluorescence and NMR methods to evaluate interactions of metal ions, phospholipids and lipoproteins with prothrombin, coagulation Factor IX, X1, and X2, and to a limited extent, Factor VII. We will evaluate paramagnetic probes such as Mn2 ion and Gd3 ion, as well as the fluorescence probe Tb3 ion, as potential substitutes for Ca2 ion in order to obtain information as to the role of the metal binding site in phopholipid (lipoprotein) - coagulation Factor interactions, utilizing the characteristics of these metal ion probes. We will conduct studies aimed to evaluate a possible function of circulating lipoproteins in blood coagulation and examine the nature of the interaction of these lipoproteins with Factors VII, IX, X1 and X2, as well as prothrombin. Finally, we wish to utilize fluorescence, NMR, and pulsed laser methods to evaluate the nature of the conformational change produced in the above mentioned blood coagulation proteins as a result of cooperative binding of metal ions.